1. Field of the Invention
This invention relates to vibrators and in particular to fluid-operated vibrators.
2. Description of the Prior Art
In U.S. Pat. No. 2,215,888, of Gerald F. Swarthout, a vibrator structure is disclosed wherein a portion of the hydraulic fluid driving the hydraulic motor escapes into a lower portion of the casing so as to lubricate the bearings. The casing is open to the exhaust conduit so that the pressure of the lubricant in the casing is at exhaust pressure.
In U.S. Pat. No. 2,099,280 of Ernest H. Shaff, a radial duct is provided for conducting air carrying a quantity of grease to be distributed throughout the cylinder.
Robert W. Baily, in U.S. Pat. No. 2,148,722, shows a submersible vibrator wherein the spent motor fluid is exhausted into a space in the motor casing.
In U.S. Pat. No. 3,272,138, of Eugene N. Connoy et al, escapement of fluid from the pressure zone through a running clearance permits lubrication of the bearing. The lubricant then flows through a passage means to a hollow interior of the pump body to be exhausted therefrom through a drain port passage.
Oystein Bjorndal, in U.S. Pat. No. 3,299,825, teaches the provision of an inlet to the gears for providing a low pressure lubricant thereto.
In U.S. Pat. No. 3,395,894, of S. Hedelin, a bearing cup embraces the body and is provided with grooves for lubricant circulation. A filling hole for the lubricating oil is further provided.
In U.S. Pat. No. 3,566,915, of Willis D. Griffin, a pressure hose of a hydraulic system is enclosed within a return hose and a special coupling is provided for providing connection of both the high pressure and low pressure conduits to the work element.
In U.S. Pat. No. 3,719,251, of John R. Hedrick, a diffuser apparatus is disclosed having a central hose extending longitudinally through an outer hose.
Frank L. Burton, in U.S. Pat. No. 3,831,635, discloses coaxially arranged hoses providing a flexible sleeve at the free end of the hose for protecting the user in the event of rupture.
In U.S. Pat. No. 2,838,074, John A. Lauck discloses a fluid pressure hose having coaxially related portions to define a hose within a hose assembly for transferring fluids from a pressure source to a pressure-utilizing device.